Problem: $ D = \left[\begin{array}{rrr}5 & 3 & 1 \\ 2 & 2 & 4 \\ 7 & 1 & 5\end{array}\right]$ What is $ D^{T}$ ?
Solution: To find the transpose, swap the rows and columns. $ D^{T}$ = $\left[\begin{array}{rrr}5 & 2 & 7 \\ 3 & 2 & 1 \\ 1 & 4 & 5\end{array}\right]$